Did You Know :: Marine Invasive Species

 

 

Aquatic invasive species are plants and animals that evolved in one location and are introduced through a variety of means into another location.

Species have always used the oceans to move about the planet. By swimming or hitching a ride on a log, leaf, or coconut, organisms have found new worlds in which to thrive. But until recently, this process has been moderate, limited by the currents and the winds.

Did You Know :: Overfishing

 

Ocean overfishing is simply the taking of wildlife from the sea at rates too high for fished species to replace themselves. The earliest overfishing occurred in the early 1800s when humans, seeking blubber for lamp oil, decimated the whale population. Some fish that we eat, including Atlantic cod and herring and California's sardines, were also harvested to the brink of extinction by the mid-1900s.

Highly disruptive to the food chain, these isolated, regional depletions became global and catastrophic by the late 20th century.

Did You Know :: M101 @ Pinwheel Galaxy

This composite image of M101 (aka, the "Pinwheel Galaxy") combines data from four of NASA's space-based telescopes. X-rays from Chandra (purple) reveal the hottest and most energetic areas due to exploded stars, superheated gas, and material falling toward black holes. Infrared data from Spitzer (red) shows dusty lanes in the galaxy where stars are forming, while Hubble data (yellow) traces the light from stars. Ultraviolet emission detected by GALEX (blue) shows emission from young stars.

Source : Chandra x-ray observatory

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Management Team

Melaka Planetarium Adventure Science Centre

Did You Know :: Surprisingly Bright Super Bubble

This composite image shows a superbubble in the Large Magellanic Cloud (LMC), a small satellite galaxy of the Milky Way located about 160,000 light years from Earth. Many new stars, some of them very massive, are forming in the star cluster NGC 1929, which is embedded in the nebula N44, so named because it is the 44th nebula in a catalog of such objects in the Magellanic Clouds. The massive stars produce intense radiation, expel matter at high speeds, and race through their evolution to explode as supernovas. The winds and supernova shock waves carve out huge cavities called superbubbles in the surrounding gas. X-rays from NASA's Chandra X-ray Observatory (blue) show hot regions created by these winds and shocks, while infrared data from NASA's Spitzer Space Telescope (red) outline where the dust and cooler gas are found. The optical light from the 2.2-m Max-Planck-ESO telescope (yellow) in Chile shows where ultraviolet radiation from hot, young stars is causing gas in the nebula to glow. 

A long-running problem in high-energy astrophysics has been that some superbubbles in the LMC, including N44, give off a lot more X-rays than expected from models of their structure. These models assume that hot, X-ray emitting gas has been produced by winds from massive stars and the remains of several supernovas. A Chandra study published in 2011 showed that there are two extra sources of N44’s X-ray emission not included in these models: supernova shock waves striking the walls of the cavities, and hot material evaporating from the cavity walls. The Chandra observations also show no evidence for an enhancement of elements heavier than hydrogen and helium in the cavities, thus ruling out this possibility as a third explanation for the bright X-ray emission. Only with long observations making full use of the capabilities of Chandra has it now become possible to distinguish between different sources of the X-rays produced by superbubbles.

Source: 

Chandra x-ray observatory

www.nasa.gov/

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Management Team

Melaka Planetarium Adventure Science Centre

Did You Know :: VESTA - "Asteroid" or Another "Dwarf Planet" ?

Vesta : Image taken by Dawn Spacecraft

Vesta, formally designated 4 Vesta, is one of the largest asteroids in the Solar System, with a mean diameter of about 525 kilometres (326 mi). It was discovered by Heinrich Wilhelm Olbers on 29 March 1807, and is named after Vesta, the virgin goddess of home and hearth from Roman mythology.